Man-hole cover for boilers



(No Model.)

F. TROWBRIDGE. MAN HOLEGOVEB. FOR BOILERS.

No. 320,512. Patented June 23, 1885.,

UNITED STATES PATENT triers.

FRANK TROWVBRIDGE, OF FOND DU LAC, \VISCONSIN.

MAN-HOLE COVER FOR BOILERS.

EJFEGIFICATION forming part of Letters Patent No. 320,512, dated June23, 1885.

Application ti ed March 9, 1885.

To all whom it may concern.-

Be it known that I, FRANK TROWBRIDGE, a citizen of the United States,rcsiding at Fond du Lac,in the county of Fond du Lac and State of Wisconsin, have in ented certain new and useful Improvements in Man-Hole Covers for Boilers, of which the following is a specification, reference being had therein to the accompanying drawings.

My invention relates to man or hand hole plates or covers for use on steam-boilers, sewers, 850.; and it consists in the construetion,arrangement, and combination of parts,substantially as hereinafter described, and more particularly pointed out in the claims.

In the drawings, Figure 1 represents a trans verse section of a man or hand hole plate or cover in position upon a man or hand hole and provided with my improvement. Fig. 2 represents atop plan view of the cover shown in Fig. l in position. Fig. 3 represents in elevation a man or hand hole plate or cover, as heretofore constructed.

Heretofore plates or covers forman or hand holes in steam-boilers, sewers, &c., have been provided with securing bars or bolts rigidly attached at one end to said plates or covers at the middle thereof and extending thence outwardly at right angles to the longitudinal and transverse axes thereof. This form is shown in Fig. 3, and, as is well known to those skilled in the art to which my invention appertains, is open to serious objections on account of the fixed bolt operating to prevent the free removal of the plate or cover from the interiorof the boiler, sewer, 850., without danger of displacing or of injuring the packing surrounding said cover or plate. The objection above named is more especially true in cases where hand-holes are employed, which of necessity are small, the covers or plates thereof in many instances having securingbolts equal to or exceeding in length the diameter of the cover or plate,

As will be readily understood, the above-described hand-hole cover or plate cannot be removed from a boiler or other position without great trouble and annoyance, caused by the securing bolt or rod catching against the edge of the man or hand hole. To obviate this objection my invention contemplates a securing rod or bar hinged to the plate or cover and (No model.)

adapted to be turned down upon the upper surface thereof when it is desired to remove the same from its position on a boiler, sewer, &c. g

Referring to the drawings, in which like letters of reference indicate like parts in all the figures, A designates a portion of the shell of a steam-boiler having a man or hand hole, A, protected by a cover, B, having an outwardly-projecting flange, Z), a little below the upper surface thereof. In Fig.3 I illustrate the old form of cover in general use, in which the bolt B is rigidly secured to the cover about centrally, said cover being oval-shaped and closely fitting the hole or aperture A, of corresponding shape but of smaller diameter.

In my improved construction, (shown in Figs. 1 and 2,) I employ a cover similar in its construction to the one above described; but, in lieu of connecting the rod or bolt 13 rigidly thereto, I employ two bolts, C O, having screw-threaded shanks c screwing into the cover and provided with or formed into eyes at their upper ends, as at 0, through which passes a bolt,D,the lower end of the bolt or rod B being formed into an eye or loop,which fits over the bolt D and between the eyebolts 0, thus providing a hinged connection therefor with the cover. The eyebolts are secured to the cover,near the middle thereof, and a short distance apart from each other, on opposite sides of a line drawn through the longitudinal axis of the cover, as clearly shown in Fig. 2, the crossbolt D passing transversely through said eyes and thus adapting the rod 13 to fold down against the upper surface and in alignment with the longitudinal axis of the cover. To this construction, adaptation, and arrangement of parts I attach importance, as therein lies the gist of my invention.

E designates the bridge, preferably of arch shape, and having at its lower end outwardly and downwardly projecting flanges e e,respectively,which bear against the edges of the boilershell, as shown, while at its upper end said bridge is provided with an enlarged portion through which passes the upper screw-thread ed end of the bolt B. A nut, F, fits over the said screw-threaded end of said bolt and bears upon the upper surface of the enlarged portion. G designates a gasket or packing-ring,

of rubber or other suitable material, interposed between the flange b of the cover B and the inner surface of the boiler adjoining the man or hand hole. The packing-ring may be constructed after any of the well-known forms now in use.

The application of a cover provided with my improvement to a man-hole or hand-hole is as follows, to wit: The securingbolt B having been folded upon the cover, the latter is then passed endwise through the man or hand hole, after which the bolt B is turned into a perpendicular position and its screwthreaded end passed through the aperture at the top of the bridge E, and the nut F secured thereto, as shown in Fig. 1.

To remove the cover from a man orhand hole the nut F is first taken from the bolt B and holes having covers provided with fixed securing-bolts, as shown in Fig. 3it is necessaryto wholly remove the bolt from the cover before removing said cover from its position.

Having thus described my invention, I would have it understood that I do not limit myself to the exact details of construction shown and described by me as an embodiment of my invention; but

What I claim, and desire to secure by Letters Patent of the United States, is-

1. In a man or hand hole cover for steamboilers, sewers, &c., the combination of the cover, screw-eyes, a pivotal bolt, and cover- W 

